1. Field of the Invention
The present invention generally relates to an apparatus and a method for manufacturing a liquid crystal display panel. More particularly, the present invention relates to a technique of injecting a liquid crystal material in a liquid crystal display panel including film substrates.
2. Description of the Related Art
In recent years, display devices including flexible film substrates instead of conventionally used glass substrates have been developed in the fields of liquid crystal displays, organic EL (Electro Luminescence) displays, and the like.
For example, Japanese Published Patent Application No. S62-66229 discloses a manufacturing method of a liquid crystal display device (a liquid crystal display panel) in which a pair of flexible substrates, such as plastic films, having upper and lower electrodes formed thereon are positioned so as to face each other, and are bonded in this state with an adhesive along the whole periphery except a portion serving as an injection port, and a liquid crystal material is injected from the injection port. In this manufacturing method, the injection port is formed in a corner, and the corner is cut after the liquid crystal material is injected and sealed. Japanese Published Patent Application No. S62-66229 describes that, according to this method, only a very small portion of the outer surface of the device gets wet with the liquid crystal material, which saves the liquid crystal material and suppresses contamination and degradation of the liquid crystal material.
Incidentally, a roll-to-roll method capable of continuously processing a film substrate is preferable in terms of productivity to manufacture a liquid crystal display panel using film substrates.
In this roll-to-roll method, a one drop fill (ODF) method has been invented, in which a liquid crystal material is injected between a pair of film substrates by, for example, first dropping the liquid crystal material onto one film substrate having a frame-shaped sealant formed thereon, and then bonding this film substrate and the other film substrate under vacuum so that no air bubble is introduced therebetween.
If a manufacturing process of the roll-to-roll method involves a vacuum process using such an ODF method, however, a processing chamber for bonding the pair of film substrates need to be evacuated for every processing unit, which reduces the manufacturing efficiency.